Sail, parachute, airplane wing, and the like



June 28, 1932.V P. A. vAlLE 1,864,964

sAIL, PARACHUTE, AIRPLANE WING, AND THE LIKE Filed Aug. 30, 1950 2Sheets-Sheet l June 28, 1932. P. A. vAlLE SAIL, PARACHUTE, AIRPLANEWING, AND THE LIKE Filed Aug. so, 1950 2 Sheets-Sheet 2 Patented June28, 1932 UNITED STATES PATENT OFFICE PEMBROKE A. VAILE, OF CHICAGO,ILLINOIS, ASSIGNOR OF ONE-HALF TO SHELDON CLARK, OF CHICAGO, ILLINOISSAIL, PARACHUTE, AIRPLANEWING, AND THE LIKE Application filed August 30,1930. Serial No. 479,056.

This invention relates to improved means of obtaining an area ofnegative pressure or vacuum on moving bodies, such as sails, parachutes,airplane win-gs and the like.

It is recognized that the major portion of the lift in the conventionalairplane is ,obtained from the vacuumI or area of negative pressureabove the wing or wings of the machine. The shape of the forward portionof the wing adjacent to andabove the front part or leading edge of thewing determines the line of the air-stream and consequently the locationand extent of the suctional area above the wing.

It has been discovered that the suctional action of this vacuum or areaof negative pressure operates in an analogous manner in the act ofsailing boats and especially when sailing against the wind, beating ortacling, as it is called in nautical langauge, and that the power of thesuction or negative pressure on the lee side of the sail is actuallygreater than the positive pressure on the windward side of the sail.

It is also my belief that as a parachute moves through the air thegreater portion of the resistance is provided by the outer and upperportion of the fabric and not by the inner and lower portion thereof.

Following this line of reasoning I have endeavored to provideair-streams of such form as toincrease the suctional effect of the areaof negative pressure, the means whereby this end is achieved beingdescribed herein and shown inthe accompanying drawings.

In the drawings:

Fig. 1 is a side elevation of a sailboat embodying my invention.

Fig. 2 is an enlarged view showing the leading edge or lulf of amainsail to which the invention has been applied, the mast being brokenaway to reveal the construction of the sail.

Fig. 3 is an enlarged fragmentary view showing details of constructionof the sail.

Fig. 4: is a sectional view taken on the line 4 4.- of Fig. 3.

Fig. 5 is a plan view of the boat and mainsail with air currentsindicated diagrammatically.

Fig. 6 is a side'elevation of a parachute, partly in section.

Fig. is an end elevation partly in section p f an airplane wingembodying my invenion.

Fig. 8 is a fragmentary front view of the same.

Referring now to that embodiment `of the lnvention shown in Figs. 1 to 5inclusive of the drawings, the boat is indicated at 10, the mast at 11,the mainsail at 12, spreader 1F, boom 14 and jib l5.

` My invention has been embodied in the mainsail 12 but obviously it mayalso be applied to other sails.

The leading edge of the sail 12 is provided with means for deflectingthe normal airstream on the side of the sail opposite the side ofpositive pressure. One means for accoms plishing this result is shown inthe drawings. In Fig. 3 the leading edge of the sail 12 is shown as cutaway on the curved line 16 and a piece of fabric 17 full enough to forma pocket is shown in Fig. 4 as stitched to the fabric 12 adjacent thecut away edge. A plurality ofsuch pockets 17 are so located betweengrommets 18that they do not interfere with the usual fastening of thesail to the mast. Midway between the two ends of the forward edge of thepocket 17 at one side of the fabric is an eye 19 and at the oppositeside an eye 20. Any desired number of pockets 17 may be provided butpreferably they extend from the foot of the sail to a point near itshead.

A rope 21 is laced into the eyes 19 and a similar rope 22 through theeyes 20. These ropes may be secured to the spreader arms 13 as shown inFig. 2 and be adjustably secured to the deck 23 by a block 24 and cleat25. In Fig. 2 the rope 22 is shown taut and consequently the pockets17are drawn toward the left of the leading edge of the sail 12. This is4the position said pockets are intended to assume when the wind isdirected toward the left side of the sail as shown in Fig. 2. When thedirection of the wind is toward the right side of the sail the rope 21is made taut and the rope 22 is slack and the fabric forming the pocket17 is drawn toward the right, as shown in dotted lines in Fig. 2.

In Fig. 5 I have indicated the boat as sailing close to the wind, thenormal air-stream being indicated byarrows a, the pockets being opentoward the Windward side to receive and deflect the wind, therebyproducing an air-stream Z) which is at an angle to the normalair-stream. This deflected stream I;

cutting across t-he normal stream, sends the air current c on theleeward side awa-y from that side of the sail and thereby increases thearea d of negative pressure on the side opposite the positive pressure.

The air pockets catch the wind and divert it, thus forming a deeper andmore extensive suctional area than the normal one and consequentlyincrease the powerv of the sail and the speed of the boat.

Instead of using pockets 17 a plurality of spaced apart apertures or a.longitudinally extending slot may be arranged slightly inwardly of theleading edge of the sail 12 to create deflecting air-stream o.

Referring to Fig. 6, the application of the principle of this inventionto the parachute is to provide the parachute. 30 with a considerablenumber of apertures 31 adjacent to its leading edge or lower portionduring descent, so as to allow almost all of the air that cannot beusefully employed to escape in substantially horizontal streams throughthe walls of the fabric instead of spilling immediately upwardly fromthe leading edge and conforming closely to the contour of the parachute.

The apertures may be of any desired shape, preferably circular, and theleading edge of the parachute should be scalloped or cut as shown at3.3, preferably with the V shaped cuts shown, to each point of which avrope or cord is attached to keep the V shaped point extended. I preferto eliminate the central opening usually providedY in parachutes.

The value of the irregular edge lies in the fact that it inducesvariations of air current which cross each other and tend to extend theordinary drag that would otherwise take place around the leading edge ofthe parachute and this naturally sets up greater resistance togravitation and tends to widen the area of negative pressure.

The cross currents produced by the spilling of the air around theparachute edge as well as by the substantially horizontal air currentsrushing out of the apertures 31 together create a ring of air currentsabout the parachute which actf'as deflectors of the normal air currentsto throw said normal currents farther away from the descendingparachute, thereby creating a greater vacuum above the parachute andconsequently stronger resistance to gravitation.

In the flight of an airplane the air in front of the wing is influencedby the passage of the wing or wings through the air to a distanceapproximately equal to the chord of the wing, that is, the distance fromthe front or leading edge to the rear or trailing edge, and it isobvious that there must be in front of the leading edge a considerableamount of compression of the air before it is diverted upward by thecurve of the wing in order to provide the most effective suctional areaor areas of negative pressure on top of the wing. Although this pressureundoubtedly exists the air-stream against the leading edge caused by thepassage of the plane through the atmosphere is very elastic andpractically uncontrolled.

It is my purpose to confine the air-stream to more specific paths and tomore definitely direct it against the defiecting edge of the wing, byproviding the leading edge of the plane wing l0 with a. series ofinverted U shaped channels l1 a suitable distance in front of theleading edge of the plane. These may be either continuous or separatedand they may if desired have a funnel shaped flange to furtherconcentrate the air flow on the leading edge of the plane.

Changes may be made in details of con struction without departing fromthe scope of my invention and I do not intend to be limited to the exactform shown and described except as set forth in the appended claims.

I claim:

1. A body adapted to move through the air, provided with pockets fordelecting the normal air stream adjacent one side of the moving body toproduce an area of negative pressure adJacent the body.

2. A sail, a series of pockets on the leading edge of the sail, andmeans for adjusting the position of the pockets relative to the sail.

3. A sail, fabric forming a series of pockets secured to the leadingedge of the sail, eyelets secured to each side of the fabric pockets,and ropes secured to a fixed support, each rope laced through theeyelets at one side of the pockets for adjusting the position of thepockets.

In testimony, that I claim the foregoing as my invention, I affix mysignature, this 22nd day of August, 1930.

PEMBROKE A. VAILE.

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